1. Technical Field
The present invention pertains to temperature sensing and monitoring systems. In particular, the present invention pertains to systems for measuring and displaying the temperature of intravenously delivered fluids and other medical items.
2. Discussion of Relevant Art
Intravenously delivered fluids and other medical items are generally required to have temperatures within specific temperature ranges in order to avoid serious injury to a patient. Although there exist warming systems to heat items to their corresponding temperature ranges, medical personnel generally do not have a manner in which to ascertain temperature of the items once the items have been removed from those systems. In addition, medical personnel generally do not have a manner in which to ascertain fluid temperature during infusion into a patient. The relevant art has attempted to overcome these problems by providing a manner in which to measure and indicate temperature of fluids prior to delivery to a patient. For example, U.S. Pat. No. 522,866 (Weinhagen et al), U.S. Pat. No. 803,352 (Meyer) and U.S. Pat. No. 2,204,764 (Mayo) disclose containers having thermometers attached thereto for indicating the temperature of fluid residing in the containers. The containers are constructed to enable the thermometer bulb to access the fluid for temperature measurement.
U.S. Pat. No. 3,864,976 (Parker) discloses a laminated digital thermometer secured to a container, such as a wine bottle or a baby bottle, for determining the temperature of a fluid contained therein. The thermometer is in the form of a digital thermometer strip providing a specific digital temperature indication of fluid within the container.
U.S. Pat. No. 4,859,360 (Suzuki et al) discloses a blood bag having a temperature-monitoring device in the form of a tag or label adhered to the bag outer surface. The temperature-monitoring device includes plural reversible temperature indicators each associated with a specific temperature range to indicate a current temperature of the blood, and an irreversible temperature indicator to indicate that the blood has currently or previously reached a predetermined temperature. The reversible indicators individually provide visual indications in response to the current blood temperature being within a corresponding range, while the irreversible indicator maintains a visual indication once the predetermined temperature has been reached.
With respect to ascertaining fluid temperature during infusion, U.S. Pat. No. 3,651,695 (Brown) discloses a temperature indicator for fluid conduits that changes color in response to temperature. A color reference chart is provided adjacent the indicator to indicate the temperatures corresponding to the color variations.
U.S. Pat. No. 5,806,528 (Magliochetti) discloses an irrigation fluid delivery system including a fluid delivery tube having a temperature sensing device for measuring and providing a visual indication of the fluid temperature prior to delivery to a patient. The temperature sensing device is disposed in the tube in stripe form and typically exhibits at least one color change in response to a change in temperature to indicate fluid temperature.
The relevant art suffers from several disadvantages. In particular, the Weinhagen et al, Meyer and Mayo devices require special attachment mechanisms to affix thermometers to containers, while the containers are configured to provide the thermometers with access to the fluid, thereby increasing complexity and cost of these systems. Further, in the case of medical or sterile fluids, these systems enhance the possibility of fluid contamination, thereby risking injury to a patient. Moreover, since the thermometers tend to be rigid and fragile, the thermometers may be easily damaged during transport and/or storage of the containers. In addition, thermometer temperature indications tend to be difficult to read, thereby requiring additional time and complicating ascertainment of the fluid temperature.
Although the Parker and Suzuki et al temperature devices are less intrusive and display a specific digital temperature indication of a fluid, these devices operate within a narrow temperature range. Thus, the Parker and Suzuki et al temperature devices are limited in application to fluids having acceptable temperatures within a specific and narrow temperature range. If a fluid temperature extends beyond that narrow range, these devices do not provide a manner in which to indicate that temperature.
The Brown and Magliochetti systems do not provide a specific temperature indication. Rather, these systems employ color indications requiring users to reference or recollect the temperature color scheme, thereby requiring additional time and complicating ascertainment of fluid temperature.